If you see the errors described above check your inodes. What does 'df -i' return?

Support got back to me and we found that /opt/zimbra had run out of inodes.

We ran out of inodes because convertd was choking on winmail.dat files
from the past from the imapsync. had to bring zimbra down to clean them
out. remount and bring it back up. convertd has been disabled until the
import is done. This means webmail searches won't return new attachments
for now.

I'm having this issue with 6.0.2 and outlook clients - could one of the zimbra staffers give us unix noobs a step by step to the fix fultonj mentions here? some advisory on any repercussions would also be good.

To see if we have the same problem simply run 'df -i' and see if you have run out of inodes, which are a file system thing, not a Zimbra thing (google it if you are not sure). If you ran out, then delete files. In my case attachment indexing made too many so I cd'd to that directory and did an 'rm *' (make sure you're in the right directory

OS X uses inodes too (it's a Unix file system thing, and OS X's HFS+ is unix like). Please post the output of 'df -i' and we'll see if you're full or not before bothering to find the relevant directory.